Why switch to 2G pistons?

[Dieselboy]

Im getting a new 6 Bolt motor and Im concidering getting 2G pistons. Now I know 2G's have a slightly higher C/R (I believe its 8.5:1 for 2G's and 7.8:1 for 1G's). So what would be a benifit of switching from the 1G to the 2G pistons?

 

[cucumber]

You've answered your own question, the higher compression ratio.

 

[Dieselboy]

But why run higher C/R if your running higher boost?

 

[Talondsm18g]

More power.

 

[Dieselboy]

So do they make quite a difference in the low end power? Better drivability? How much can I expect to pay for a set of these used?

 

[Dieselboy]

Oh yeah, how is their durability compared to the 1G's? Any diff?

 

[harryb]

Derek-
I have 2G pistons on my 1G big rods. It pulls hard compared to other cars with just the 1g piston/ 1g rod combo. Get them. My engine is strong all things considered. You will be dissappointed if you don't get these. It's a small step that will help you much more later on in the process in building your car.

 

[Dieselboy]

Originally posted by harryb
Derek-
I have 2G pistons on my 1G big rods. It pulls hard compared to other cars with just the 1g piston/ 1g rod combo. Get them. You will be dissappointed if you don't get these. It's a small step that will help you much more later on in the process in building your car.

With all this said, I have better piece of mind now, thanks Harry. So how much can I expect to find a used set of these badboys?

BTW harryb: Are you going to beable to make it to the Wash/Ore meet on Jan. 4th?

 

[danthman3]

used pistons?
pick up some for about 200 (new) and have the rods machined to fit
or you can get a set-up press fitted together from shops like turbotrix

 

[harryb]

Derek-
No I won't be able to make it to the meet in Portland. I've got to work and have family visiting also. Sorry man, wish I could make it. Also just get new pistons. Used would be to much hassle finding perfect ones.
-Todd

 

[Dieselboy]

Originally posted by danthman3
used pistons?
pick up some for about 200 (new)

Thats it from the dealer??? Whats the difference from press fitted to normal? Benifit, what would you recommend?

 

[Dieselboy]

I never knew they were that cheap, I never woulda guessed

 

[marksae]

Lower compression will let you run more boost w/o detonating. Running higher boost will help you guys w/ big turbos run them in their effiency ranges. Your off-boost response won't be as good though. If you race a lot, I'd just stick w/ stock 1g pistons and just boost the hell out of them. The durability of the pistons are the same. They're good for at least 470whp.

 

[candela]

No no no, get em.... everyone has em and thats for a reason. I have them in my last setup and noticed about a 100rpm decrease in full boost threshold. They will hold just as muhc power and are perfect for reliability. Theres no question for this at all... 2g's run them stock which, only thing they dont have is the big rods underneath em There are many posts about this with some goo dinfo on em to. But basically the rods and pistons need to be machined/opened up cause they are a bit to small to fit together. Turbo trix sells them already together http://www.turbotrix.com/parts/engine.shtml



AUstin

 

[Tevenor]

Unless a piston has gone through hell, you can by used ones and they will work fine. Hell I have at least 2 sets of them for sale.

 

[BUCK]

Originally posted by candela
No no no, get em.... everyone has em and thats for a reason. I have them in my last setup and noticed about a 100rpm decrease in full boost threshold. They will hold just as muhc power and are perfect for reliability. Theres no question for this at all... 2g's run them stock which, only thing they dont have is the big rods underneath em There are many posts about this with some goo dinfo on em to. But basically the rods and pistons need to be machined/opened up cause they are a bit to small to fit together. Turbo trix sells them already together http://www.turbotrix.com/parts/engine.shtml AUstin

OR??

"Lower compression will let you run more boost w/o detonating. Running higher boost will help you guys w/ big turbos run them in their effiency ranges. Your off-boost response won't be as good though. If you race a lot, I'd just stick w/ stock 1g pistons and just boost the hell out of them. The durability of the pistons are the same. They're good for at least 470whp"... marksae


WHICH IS IT? Where is a guru when you need one?

My original 1G pistons are OK but I have 2 bent rods - gotta decide which way to go...

 

[candela]

Look, if you can tune, or wil have someone tune for you then dont worry about it. 8.5 isnt much, and although it will give you a smaller margin of tunability you will make more power with less boost. It will give you better low end, spool up as well as overall power. Its a very safe ans reliable upgrade from the 7.8 You will find many poeple have done it wiht no problems at all and are very happy with the upgrade including myself.

 

[4pistons]

The higher compression of the 2G pistons really do help throttle response off boost. You'll notice it just driving around. Where is the threshold for trading boost vs compression on a race motor? I don't know. Not sure anyone can answer that conclusively. Most race guys go with aftermarket forged that fit their particular combo and are done with it.

If you need the specs for machining the rods you can find my page at http://hometown.aol.com/rcm1061/myhomepage/auto.html or link to it through the VFAQ site where it's listed.

Rick - '91 GSX

 

[Dieselboy]

Well, my mind is made up, Im searchin' for 2G pistons...

Originally posted by Tevenor
Unless a piston has gone through hell, you can by used ones and they will work fine. Hell I have at least 2 sets of them for sale.

So....wanna sell me a set? If their in good condition, email me at [email protected] and Ill buy em. I got cash, gimmie a price shipped and well deal. Thanks man.

 

[BoostinAWD]

Well what exactly needs to be done to the 2g pistons to get them to fit to the 1g big rods? I looked at that diagram but its a little misleading, why does it say the crank end needs to be enlarged?

Don't I just need to do the piston end? I know the hole needs to be largened but why does it need to be narrowed? Getting the rods machined using that diagram means that I will still need to have them press fitted right?

Just making sure because I just got my block tore apart and honed. I ordered a set of 1g big rods that were already balanced, shotpeened and had arp studs pressed in. And I ordered a set of 2g standard pistons and rings.

I was shocked when I pulled the head off. After 190,000 miles the factory crosshatching was still their. Crazy...

 

[HighPsi91]

The small end of the rod has to be narrowed 0.100" and bored to accept a 22mm wrist pin. Nothing gets done to the crank end.

 

[WhipmastaFlex]

i just ordered wiseco forged pistons for my 2G and i have no clue as of right now what my C/R is going to be until they're in and we run a test. anyone have experience with them? can't be any worse than the 55lbs i had in cylinder 3 when my stock piston detonated...

Adam

(notice the scored cylinder wall from the aluminum deposits. also, the chunks missing off the edge of the piston from the detonation )

 

[UltraImports]

I stuck with 1g's....well....cause I'm broke. I figure if I really need to, I'll save up and buy the good stuff down the road.

 

[4pistons]

I looked at that diagram but its a little misleading, why does it say the crank end needs to be enlarged?

I am the author of that page and you're right it is a little misleading. Nothing needs to be done to the big end. The dimensions listed are the high and low end end of the bore which your machine shop will need to properly recondition the rod and fit the piston. The difference in those dimensions os .0008". If you print that page and bring it to the shop they should have no problem.

I know the hole needs to be largened but why does it need to be narrowed? Getting the rods machined using that diagram means that I will still need to have them press fitted right?

It must be narrowed to allow enough clearance between the rod and the piston as it pivots. They will still be press fit, yes.

I ordered a set of 1g big rods that were already balanced, shotpeened and had arp studs pressed in.

If you had new bolts put in be sure they trued up the big end hole and put it back to round.

Rick - '91 GSX

 

[Vegas Smith]

man, pullin pistons scares the hell out of me. the most ive done is change a clutch, and a timing belt. goodluck diesel!